squeaking from rear wheel

[nlaw]

Any ideas please…I drive an '06 E63, had all brake discs replaced 2 weeks ago. Set out on a short 5 mile round trip yesterday..about half way to destination I hear what sounds like a bird whistling coming from the rear nearside wheel area, not associated with breaking, the squeaking/whistling appearing to get louder the longer it's driven.
Anyway took it to a specialist garage, couldn't hear the squeak (was raining..so I guess a bit of moisture rectified the sound)..they are looking into it and reckon it's something to do with a coil in the handbrake mechanism rubbing against the whatever. In addition a week ago they have advised I get the near side rear shock absorber replaced as is currently leaking a bit of oil, so not sure if this may be relevant though they did not mention this as a possibility.

Cheers

[television]

The brake back plate can rust badly allowing the parking brake mechanism to touch the drum. Also the spring clip can break. I have known many cars a little older to do this.

[nlaw]

thanks, all sorted it seems, needed new handbrake shoes and springs which had collapsed possibly due to the handbrake sticking